This invention relates to storage battery assemblies, and more particularly, to a connection arrangement for battery monitoring circuits that monitor conditions and/or operating parameters of storage batteries that are used in deep cycle applications, or for motor vehicle batteries, and the like.
Storage batteries are often used in deep cycle applications to provide electrical energy to power electrical devices such as electric motors or emergency lighting. Typical deep cycle applications for a battery include providing power to lights and accessories in recreational vehicles, providing power to an electric trolling motor in a fishing boat, providing power to the electric drive of a battery-operated wheelchair, or providing back-up and emergency power for security systems. There is also a great deal of interest in the adaptability of storage batteries to "electric cars". In such applications, the storage battery may be required to supply current for several hours. Supplying this current will discharge the battery to a relatively low state of charge. In view of this, batteries are being produced which include a state of charge monitoring circuit for providing a visual or audible indication when the state of charge of the battery has fallen below a predetermined threshold. Examples of battery state of charge monitoring circuits are disclosed in the U.S. Pat. No. 5,130,699 to Michael Reher et al. which was issued on Jul. 14, 1992 and which is assigned to Globe Union Inc., and in the co-pending U.S. patent application Ser. No. 08/030,648 of Michael T. Reher et al., which was filed on Mar. 12, 1993 and which is assigned to Globe Union Inc.
Although such monitoring circuits are particularly suited for deep cycle applications, the monitoring circuits can be used in other applications, such as for monitoring one or more operating parameters of storage batteries used in motor vehicles and providing an output indicative of the monitored condition for use by the vehicle computer for control and diagnostic purposes. For example, the U.S. Pat. No. 5,321,627 to Michael T. Reher which was issued on Jul. 14, 1992 and which is assigned to Globe Union Inc., discloses a battery monitor which provides an indication of the absolute state of charge, the relative state of charge, and the capacity of a battery under discharge, rest, and recharge conditions, as well as other information and indications.
Most battery state of charge monitoring circuits include an electronic circuit that must be continually connected to the terminals of the battery being monitored. To facilitate such connections, the monitoring circuit is usually installed permanently into or onto the battery and connected to the positive and negative terminals of the battery. Typically, the connections to the battery terminals are accomplished through permanent copper bus bars that are molded into the battery cover using an injection molding process. This requires that the battery cover be of a non-standard size to accommodate the bus bars. In addition, the bus bars must be sized so that they can withstand the injection molding process resulting in substantially more metal than is necessary to meet the conductor resistance requirement. Studies have demonstrated that the cost of molding bus bars into the battery cover for this purpose is prohibitive. Moreover, because of their size and because the thermal expansion characteristics of the bus bars may differ from those of the cover, the bus bars must be free to move relative to the termination by which they are connected to the battery terminals.
In U.S. Pat. No. 5,159,272 to Purushothama Rao et al. which was issued on Oct. 27, 1992, there is disclosed an arrangement for installing a battery monitoring device on a battery which includes secondary terminal arms which project from the battery terminal bushings and terminate in upwardly extending conical sections defining secondary battery terminals which protrude through openings in the bottom surface of the housing of the battery monitoring device and engage terminal contacts of the battery monitoring device interiorly of the housing of the battery monitoring device. Acid proof seals are incorporated into the housing of the battery monitoring device to provide a seal at the terminal receiving openings in the bottom surface of the housing. Because the secondary battery terminals defined by the battery terminal bushings are connected directly to the circuit of the battery monitoring device, this arrangement requires relatively long secondary terminal arms, even though the housing of the battery monitoring device extends over more than half the length of the battery cover. Also, because of the size of the battery monitoring device, a non-standard cover is required to accommodate the device.